JP2007131803A - Method for producing phenolic resin foam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To lower the thermal conductivity in the temperature region not higher than the boiling point of a blowing agent in a phenolic resin foam produced by using the hydrocarbon blowing agent. <P>SOLUTION: In expansion-molding a phenolic resin by using a hydrocarbon blowing agent of a boiling point of 20°C or higher, the hydrocarbon blowing agent and a phenolic resin curing catalyst are added to 100 pts.wt. phenolic resin, 0.1 to 10.0 pts.wt. paraffin is further added to the mixture, and the final mixture is expanded and cured to obtain a foam of excellent heat insulation properties. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is a heat insulating material that is used as a heat insulating material for various buildings such as a wall material and a ceiling material of a house, a roof, and a refrigerator, especially a phenolic resin foam having excellent heat insulating performance in a low temperature region. A method is provided.

  The phenol resin foam is produced by mixing a resol type phenol resin obtained by condensing phenol and formalin with an alkaline catalyst, mixing a surfactant, a foaming agent, and a curing catalyst, and foaming and curing the mixture at room temperature or heating. As the blowing agent, hydrogenated chlorofluorocarbons (HCFC) such as dichlorofluoroethane (HCFC-141b), 1-chloro-1,1-difluoroethane (HCFC-142b), or 1,1,2-tetrafluoroethane ( It is known to use hydrogenated fluorocarbons (HFC) such as HFC-134a) and 1,1-difluoroethane (HFC-152a), or hydrocarbons such as pentane and butane.

  In recent years, not only phenol resin foam but also other urethane resin foams, styrene resin foams, polyethylene resin foams, etc. are not only in the global environment due to the destruction of the ozone layer by foaming agents and the problem of global warming. Development of foaming technology using a hydrocarbon-based foaming agent, which is a mild foaming agent, has progressed, and hydrocarbon-based foaming agents have been used (see Patent Documents 1 and 2).

  However, as a blowing agent having a low thermal conductivity generally used as a hydrocarbon-based blowing agent, normal pentane (boiling point 36.2 ° C), isopentane (boiling point 27.8 ° C), cyclopentane (boiling point 49.3 ° C). However, in all cases, the boiling point of the blowing agent is higher than 20 ° C., the thermal conductivity at 20 ° C., which is the use temperature of a standard heat insulating material, and the thermal conductivity below the boiling point of the blowing agent, There is a problem that the foaming agent in the foam becomes large due to the phenomenon of liquefaction and the heat insulation performance deteriorates.

JP-A-11-140216 WO99 / 11697 pamphlet

  The object of the present invention is to solve the problem that the thermal conductivity in the low temperature region below the boiling point of the foaming agent, which is a problem of the phenol resin foam produced using the hydrocarbon foaming agent, is increased, This provides a phenol resin foam having a low thermal conductivity even in a temperature range below the boiling point.

  In Patent Documents 1 and 2 mentioned above, by adding an aliphatic hydrocarbon, for example, paraffin, to the foaming agent, the bubbles of the phenol resin foam can be reduced, and thereby the heat of the phenol resin foam at 20 ° C. Although the present inventors have disclosed a technique capable of reducing the conductivity, the present inventors have further conducted intensive research, and as a result, the liquid paraffin is melt-mixed with a phenol resin to thereby generate heat in a wide temperature range of 20 ° C. or less. The inventors have newly found that the conductivity can be significantly reduced, thereby completing the present invention.

  That is, the present invention relates to a method for producing a phenol resin foam in which a foaming agent and a curing catalyst are mixed with a phenol resin, and the foaming agent is a hydrocarbon having a boiling point of 20 ° C. or higher. It is a method for producing a phenol resin foam, characterized in that 0.1 to 10.0 parts by weight of paraffin is mixed with 100 parts by weight and foam-cured.

  ADVANTAGE OF THE INVENTION According to this invention, the phenol resin foam which shows favorable heat insulation performance with small heat conductivity also in the wide temperature range below the boiling point temperature of a foaming agent is provided.

  In the present invention, 100 parts by weight of a phenol resin is mixed with 0.1 to 10.0 parts by weight of paraffin and foamed, so that the boiling point of a hydrocarbon foaming agent having a boiling point of 20 ° C. or higher is in a wide temperature range below the boiling point. A phenol resin foam having a significantly reduced thermal conductivity can be provided.

  The phenol resin which is a resin raw material in the present invention is heated in a temperature range of 40 to 100 ° C. using phenol and formaldehyde as raw materials and an alkali metal hydroxide or alkaline earth metal hydroxide as a catalyst, respectively, by a known method. And polymerized. The starting molar ratio of phenols to aldehydes of the resol type phenolic resin used in the present invention is preferably 1: 1 to 1: 4, more preferably 1: 1.5 to 1: 2.0. . Various kinds of modifiers such as urea, amines, amides, epoxy compounds, monosaccharides, starches, poval resins, polyvinyl alcohol resins, and lactones may be added to the resol type phenol resin. The resol type phenol resin is used with an appropriate viscosity by adjusting the water content. Although the suitable viscosity range of a phenol resin changes with foaming conditions, it is preferable that the viscosity in 40 degreeC is 1000-50000 cps (centipoise), and it is further more preferable that it is 2000-30000 cps.

  Examples of the hydrocarbon having a boiling point of 20 ° C. or higher used as a blowing agent in the present invention include normal pentane (boiling point 36.2 ° C.), isopentane (boiling point 27.8 ° C.), and cyclopentane (boiling point 49.3 ° C.). . These hydrocarbon foaming agents may be used alone or in combination. The mixing ratio of the phenol resin and the foaming agent varies depending on the desired thermal conductivity value, foaming conditions, and foaming ratio, but the foaming agent is 2 to 15 weights with respect to 100 parts by weight of the phenol resin (resin component excluding moisture content). Part is usually used.

  As the paraffin used in the present invention, paraffin wax, which is a linear aliphatic hydrocarbon having 20 to 48 carbon atoms, called solid paraffin, or liquid paraffin is used. Liquid paraffin is defined as "a very high mixture of liquid saturated hydrocarbons". Both solid paraffin and liquid paraffin are effective, but in use, liquid paraffin that is liquid at room temperature is easier to mix with phenolic resin.

  The ratio of the paraffin mixed with the phenol resin is 0.1 to 10 parts by weight, preferably 1 to 6 parts by weight with respect to 100 parts by weight of the phenol resin. If the amount of paraffin added is less than 0.1 parts by weight, the effect of lowering the thermal conductivity is not sufficient, and even if added over 10 parts by weight, the effect does not change so much and the production cost is expensive. This is not preferable.

  Further, for the purpose of foam control, surfactants generally used for the production of phenol resin foams are used, and among them, nonionic surfactants are effective. For example, a copolymer of ethylene oxide and propylene oxide, a condensate of an alkylene oxide and an alkylphenol such as nonylphenol or dodecylphenol, and the like can be given. These surfactants may be used alone or in combination. Although there is no restriction | limiting in particular also about the usage-amount, it adds and uses it in 0.5-10 weight part with respect to 100 weight part of phenol resins.

  The curing catalyst is not particularly limited, and examples thereof include aromatic sulfonic acids such as toluenesulfonic acid, xylenesulfonic acid, and phenolsulfonic acid. These may be used alone or in combination of two or more. Resorcinol, cresol, salinigen (o-methylolphenol), p-methylolphenol, etc. may be added as a curing aid. These curing catalysts can be diluted with a solvent such as diethylene glycol or ethylene glycol. Although the amount of the curing catalyst used varies depending on the type and foaming conditions, about 5 to 15 parts by weight is usually used with respect to 100 parts by weight of the phenol resin.

  As a more preferred embodiment of the present invention, it is mentioned that about 0.01 to 5 parts by weight of nitrogen is mixed and dissolved as a cell nucleating agent with respect to 100 parts by weight of the foaming agent. As the mixing and dissolving method, nitrogen may be pressurized and dissolved in the foaming agent in the foaming agent storage container, or it may be introduced into the foaming agent before mixing at the time of foaming and mixed and dissolved.

  As an embodiment of the present invention, for example, a phenol resin composition is prepared by adding and mixing paraffin to a phenol resin adjusted to an appropriate viscosity, introducing a foaming agent and a curing catalyst into a mixer, and stirring and mixing uniformly. Get. Then, the phenol resin composition is poured into a molding die, heated, foamed, and cured to obtain a phenol resin foam. The paraffin mixing method is not particularly limited, and the foaming agent may be mixed after the paraffin is previously mixed with the phenol resin, or the paraffin and the foaming agent may be mixed together at the same time with the phenol resin. Although it is good, it is preferable to pre-mix with phenol resin. As a mixing means, a hand mixer, a continuous mixing type pin mixer, or the like may be used. In the production of the phenol resin foam of the present invention, if the curing catalyst is mixed with the phenol resin composition in advance, the curing reaction proceeds before foaming and a good foam cannot be obtained. It is desirable to mix with a curing catalyst. The heating temperature and heating time vary depending on the reactivity of the phenolic resin and the amount of curing catalyst, but if the general heating temperature is around 80 ° C. and the heating time is about 60 to 120 minutes, the foam is completely foamed and cured. Is completed.

  The present invention will be described based on examples and comparative examples.

[Example 1]
As a surfactant, 100 g of phenol resin (resin component), 3 g of a copolymer of ethylene oxide and propylene oxide ("Pluronic F-127" manufactured by BASF), 1.0 g of liquid paraffin (manufactured by Wako Pure Chemical Industries, Ltd., first grade reagent) Then, 8 g of a curing catalyst (a mixture of 60% by weight of paratoluenesulfonic acid hydrate and 40% by weight of diethylene glycol) was added to a mixture of 6 g of normal pentane (boiling point 36 ° C.) as a blowing agent, and uniformly added. The mixed phenol resin composition was poured into a mold laid with a 30 cm × 30 cm × 3 cm face material and heated in a heating oven at 80 ° C. for 2 hours to obtain a phenol resin foam. Both sides of the obtained phenol resin foam were sliced to prepare a phenol resin foam having a thickness of 25 mm, and the thermal conductivity at each temperature was measured in accordance with the flat plate heat flow meter method of JIS A 1412. The measurement results of the thermal conductivity of the phenol resin foam are shown in Table 1. The thermal conductivity below the boiling point of the blowing agent was a very low value.

[Example 2]
A phenol resin foam was prepared in the same manner as in Example 1 except that 100 g of phenol resin was mixed with 3.0 g of paraffin. Table 1 shows the measurement results of the thermal conductivity of the obtained phenolic resin foam. The thermal conductivity below the boiling point of the blowing agent was a very low value.

[Example 3]
A phenol resin foam was prepared in the same manner as in Example 1 except that 100 g of phenol resin was mixed with 6.0 g of paraffin. Table 1 shows the measurement results of the thermal conductivity of the obtained phenolic resin foam. The thermal conductivity below the boiling point of the blowing agent was a very low value.

[Example 4]
After mixing 6.0 g of solid paraffin (manufactured by Wako Pure Chemical Industries, Ltd., melting point 44-46 ° C.) dissolved in 60 g of phenol resin heated to 60 ° C., the mixture was cooled to 20 ° C. A product obtained by mixing 6 g of normal pentane (boiling point 36. ° C.) as a blowing agent with 8 g of a curing acid catalyst (a mixture of 60% by weight of paratoluenesulfonic acid-hydrate and 40% by weight of diethylene glycol) can be mixed uniformly. The phenol resin composition was poured into a mold laid with a 30 cm × 30 cm × 3 cm face material and heated in a heating oven at 80 ° C. for 2 hours to obtain a phenol resin foam. The obtained phenolic resin foam was sliced to a thickness of 25 mm, and the thermal conductivity at each temperature was measured according to the plate heat flow meter method of JIS A 1412. The measurement results of the thermal conductivity of the phenol resin foam are shown in Table 1. The thermal conductivity was very low in a wide temperature range below the boiling point of the blowing agent.

[Comparative Example 1]
A phenol resin foam was prepared in the same manner as in Example 1 except that paraffin was not added to 100 g of phenol resin. Table 1 shows the measurement results of the thermal conductivity of the obtained phenolic resin foam. The thermal conductivity below the boiling point of the blowing agent was very high compared to the examples, and no satisfactory one was obtained.

Claims (1)

  In the method for producing a phenol resin foam in which a foaming agent and a curing catalyst are mixed with a phenol resin and foamed and cured, the foaming agent is a hydrocarbon having a boiling point of 20 ° C. or more, and the phenol resin contains 100 parts by weight of the phenol resin. A method for producing a phenol resin foam, comprising 0.1 to 10.0 parts by weight of paraffin mixed and foam-cured.